png: fix off by one

+ remove outdated comment

1 files changed, 1 insertions, 3 deletions

diff --git a/src/img/png.nim b/src/img/png.nim
index bd7e6206..d41360a3 100644
--- a/src/img/png.nim
+++ b/src/img/png.nim
@@ -266,11 +266,9 @@ func paethPredictor(a, b, c: uint16): uint16 =
   return if pa <= pb and pa <= pc: a elif pb <= pc: b else: c
 
 proc unfilter(reader: var PNGReader; irow: openArray[uint8]; bpp: int) =
-  # none, sub, up -> replace uprow directly
-  # average, paeth -> copy to temp array, then replace uprow
   case irow[0]
   of 0u8: # none
-    copyMem(addr reader.uprow[0], unsafeAddr irow[1], irow.len)
+    copyMem(addr reader.uprow[0], unsafeAddr irow[1], irow.len - 1)
   of 1u8: # sub
     for i in 1 ..< irow.len:
       let j = i - 1 # skip filter byte